This invention relates to jointing apparatus and methods utilized for joining smaller segments of wood products to form larger segments, and, more particularly, relates to methods and apparatus for formation of finger joints.
Structural glue-jointed wood products, such as dimensional lumber, is gaining greater acceptance for a wide variety of applications in the building and construction industry. Recognition that efficient utilization of wood resources will continue to be necessary, that reduction of flow to local land fills is a priority in many locations, and cost and reliability factors have continued to fuel the desire to make more of such jointed product available.
However, current finger-jointing technology has not changed substantially to keep pace with the demand. Scarf joints and finger joints of various types have long been utilized, improvements lying primarily in the field of new adhesives and/or adhesive application techniques. While many are acceptable for some applications, few if any of the known joints have proved effective for application under all significant loading conditions (tension, compression, bending, torsion and shear).
Moreover, greater efficiencies and ease of manufacture could still be utilized. Scarf joints, for example, require large amounts of wood removal for joint construction. Most current finger joint production requires provision of large-scale (and, thus, centralized) production facilities, thereby necessitating shipment of scrap lumber to the facility, often from great distances. Specialized handling of jointed materials due to fragility of the freshly glued joints is also often required. The shipping requirement increases cost and energy consumption for production, and deters many non-local companies from use of this alternative, while the special handling requirements increase cost and space requisites (production and storage) of such facilities. In addition to the high cost of industrial finger jointing equipment, smaller scale operations are thus discouraged.
Additionally, traditional facilities are not able to process post-consumer, possibly contaminated, lumber because the blades necessary for production of known joints are at risk of damage by foreign materials commonly found in post-construction scrap, demolition scrap, and the like. A finger joint construction modeled for use of such post-consumer scrap would, if accepted, greatly reduce the volume of land filled construction and demolition waste.
This invention provides a finger joint architecture and joint formation method and apparatus designed for use with all variety of wood product (including dimensional lumber and logs, without regard to species, and further including post-consumer scrap), and for utilization without regard to the particular loading conditions (tension, compression, bending, torsion and/or shear) which may be encountered. The finger joint architecture formation method is well adapted to smaller scale operations than heretofore known, including mobile manufacturing sites. Specialized handling of freshly jointed materials is not required, and wood removal in manufacture is minimized.
The joint forming method of this invention includes the steps of forming, at an uninterrupted end face of a first wood product section, an array of interrelated projections and cavities each interspersed in both first and second dimensions relative to the uninterrupted end face. Many of the projections are formed entirely interior the uninterrupted end face of the first wood product section. A mating array of interrelated projections and cavities are formed at a second wood product section end face, the first and second wood product section end faces thus arrayed being then joined. The projections are preferably tapered in the direction of projection. The cavities are also preferably tapered.
The cavities are formed longitudinally through the surface area of the end face and into the first wood product, each of the cavities located to cause an intersection with a part of another of the cavities at a selected distance below the surface area during formation. Plural series of projections are thereby defined wherein the projections in any one series are spaced from one another and from the projections in any adjacent series.
A wood product having substantial continuity of wood grain direction between ends of the wood product and formed from at least first and second wood product sections may thus be established with a finger joint architecture configured at each of the wood product sections. The wood product sections are adhesively secured at the finger joint architectures providing a joint located between the ends of the wood product. The finger joint architecture thus configured provides a joint that is characterized by a joint cross section showing plural endless nonlinear adhesive lines defining plural first and second section interfaces entirely interior the joint cross section.
The apparatus of this invention for formation of a joint architecture at a selected surface area of a wood product includes a plurality of rows of spaced cavity forming units connected with a driver. A guide conducts relative movement of the wood product and the cavity forming units to form the joint architecture at the selected surface area.
It is therefore an object of this invention to provide an improved finger joint architecture and joint formation method and apparatus.
It is another object of this invention to provide a finger joint architecture formation method and apparatus designed for use with all variety of wood product, including post-consumer scrap, and for a variety of utilization conditions.
It is still another object of this invention to provide a finger joint architecture formation method and apparatus well adapted to small scale operations, requiring little or no specialized handling of freshly jointed materials, and that minimizes wood product waste.
It is yet another object of this invention to provide a joint forming method for wood products including the steps of forming at an uninterrupted end face of a first wood product section an array of interrelated projections and cavities each interspersed in both first and second dimensions relative to the uninterrupted end face of the first wood product section with many of the projections formed entirely interior the uninterrupted end face of the first wood product section, forming a mating array of interrelated projections and cavities at a second wood product section end face, and joining the first and second wood product section end faces thus arrayed.
It is still another object of this invention to provide a method for establishing a finger joint architecture at a surface area of a first wood product adapted for securement at a selectively configured formation in a second wood product, the method including forming a plurality of longitudinal cavities through the surface area into the first wood product, locating each of the cavities to cause an intersection with a part of another of the cavities at a selected distance below the surface area during formation, and thereby defining plural series of projecting members wherein the projecting members in any one series are spaced from one another and from the projecting members in any adjacent series.
It is still another object of this invention to provide a joint forming method providing a wood product having substantial continuity of wood grain direction between ends of the wood product and formed from at least first and second wood product sections, the method comprising the steps of configuring a finger joint architecture at each of the wood product sections, and adhesively securing the wood product sections at the finger joint architectures providing a joint located between the ends of the wood product, the finger joint architecture configured so that the joint is characterized by a joint cross section showing plural endless nonlinear adhesive lines defining plural first and second section interfaces entirely interior the joint cross section.
It is yet another object of this invention to provide an apparatus for formation of a joint architecture at a selected surface area of a wood product having a plurality of rows of spaced cavity forming units, drive structure for driving the cavity forming units, and a guide for conducting relative movement of the wood product and the cavity forming units to thus form the architecture at the selected surface area.
With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiment of the herein disclosed invention are meant to be included as come within the scope of the claims.